David Hayman - IDReC
Transcript of David Hayman - IDReC
Can comparing models of measles introductions
into New Zealand and Ebola virus outbreaks in
West Africa lead to better control of both?
David Hayman
Acknowledgements Cambridge University, UK
Prof. James Wood
Dr Olivier Restif
Dr Ali Peel
Dr Kate Baker
Dr Alex Kamins
Institute of Zoology, UK
Prof. Andrew Cunningham
Dr Marcus Rowcliffe
University of Kent, UK
Dr Rachel McCrea
Australian Animal Health Laboratories
Agency, Australia
Prof. Lin-Fa Wang
Gary Crameri
Meng Yu
Veterinary Services of Ghana
Massey University, New Zealand
Prof. Nigel French
Dr Jonathan Marshall
Prof. Tim Carpenter
Prof. Mick Roberts
Dr Janelle Wierenga
Research and Policy for Infectious
Disease Dynamics (RAPIDD) Small
Mammal Working Group
Colorado State University, USA
Dr Colleen Webb
Dr Angie Luis
Dr Michael Buhnerkempe
Clint Leach
“The Webb Lab”
Centers for Disease Control and
Prevention, USA
Dr Michael Kosoy
Dr Amy Turmelle
Dr Charles Rupprecht
Wildlife Division of the Forestry
Commission, Ghana
Richard Suu-Ire
Bernhard-Nocht Institute, Germany
Dr Petra Emmerich
Animal Health & Veterinary
Laboratories Agency, UK
Prof. Tony Fooks
Dr Ash Banyard
Dr Nick Johnson
Dr Dan Horton
Dr Andrew Breed
Denise Marston
Dave Selden
STEPS Centre, Institute for
Development Studies, University of
Sussex, UK
Prof. Melissa Leach
Dr Linda Waldman
Dr Hayley MacGregor
University of Florida, USA
Dr Juliet Pulliam
University of Ghana
Prof. Yaa Ntiamoa-Baidu
US Geological Survey, USA
Dr Paul Cryan
Dr Tom O‟Shea
New Zealand Ministry of Health
Tomasz Kiedrzynski
Lisa Oakley
Nic Aagard
University of Otago
June Atkinson
Institute of Environmental Science
and Research Ltd (ESR), New Zealand
Ruth Pirie
Funding acknowledgements
• A framework for (zoonotic) infection studies
• Outbreak case study 1: Ebola virus in W Africa
• Outbreak case study 2: Measles in New Zealand
• Viral phylogeny – what „history‟ tells us
Talk outline
Framework
Directly transmitted infections only
Intermediate
animal host
Human infection
Spillover infection dynamics
Infection dynamics
Population dynamics
Environmental influences
(Local and global)
Anthropogenic
influences
(Local and global)
Reservoir
dynamics
Zoonotic transmission
Adapted from Wood et al., Phil. Trans. 2012
Terminology
• β (beta) : transmission coefficient
• γ (gamma) : recovery rate
• S : susceptible
• I : infected
• a : animal
• h : human
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Prevalence in populations Contact rates
Probability of infection
1 or more species
Host dynamics
Transmission dynamics
and mechanism
Environmental and
agricultural influences
Transmission mechanism
Reservoir abundance
Spatial overlap
Human risk behaviours
Immunity
Dose & duration of exposure
Pathogen genotype
Duration and proximity of contact
Practices (e.g. hand washing)
Adapted from Lloyd-Smith et al., Science, 2009
Ebola
Spillover dynamics
Ebolavirus transmission dynamics
Intra- and inter-
species
transmission
Reservoir dynamics
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Ebolavirus transmission pathways
Olival and Hayman, 2013 Viruses
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Spillover dynamics
Ebolavirus transmission dynamics
Inter-species
transmission
Reservoir dynamics
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Ebolavirus transmission pathways
Olival and Hayman, 2013 Viruses
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Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
SIR compartmental models
Hayman, in revision
deterministic
stochastic
Not all bats are equal
Hayman et al., PLoS ONE 2008; EID 2008; PLoS ONE 2010; EID 2012
Antib
ody p
revale
nce (9
5%
CI)
Seasonality and birth pulses
Seasonality and birth pulses
Peel et al., Proc. Royal Soc. B, 2014
Modelling bat birth pulses
Hayman, in revision
1 birth per female bat per year
Birth pulses might matter
Hayman, in revision
All models are wrong, but some are useful… George E. P. Box FRS (18 October 1919 – 28 March 2013)
Hayman, in revision
Infection dynamics when infection persists
Adult infected Births Juvenile infected
Hayman, in revision
1 year
Risk?
Data support model results
Antib
ody p
revale
nce (9
5%
CI)
Two birth pulses One birth pulse
Odds ratio 4.4, 95% confidence interval 2.5-8.7
Hayman, in revision Risk?
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Ebolavirus outbreaks - WHO
Weekly incidence reported
Ebolavirus outbreaks - published
Weekly incidence reported
WHO Bulletin 1976; MacNeil et al., JID 2011; Okware et al., TMIH 2002; Georges et al., JID 1999;
Khan et al., JID 1999
Ebolavirus outbreaks
Hayman et al., unpublished
Incid
ence –
cases p
er w
eek
Human ebolavirus epidemics: R0
R0 – average number of secondary cases
in a susceptible population
Hayman et al., unpublished
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Next challenge…
Ghana – ‟37‟ Military Hospital
Fresh Smoked
Bats as bushmeat
Kamins et al., Biol. Conservation 2012
Contact rates through bushmeat
Strong seasonality in hunting
Large numbers
Synchrony or
asynchrony?
Seasonality in prevalence
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Measles
New Zealand measles incidence
Cases p
er m
onth
Ebola
Hayman et al., unpublished
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Ebolavirus transmission pathways
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Measles transmission pathways
Prevalence in populations
Contact rates Probability of infection
Immigration to New Zealand, 2012
Hayman et al., unpublished
Annual measles incidence per million, 2012
Hayman et al., unpublished
Risk of measles importation?
Hayman et al., unpublished
Seasonality in immigration
Hayman et al., unpublished; Ferrari et al., E&I 2010
Synchrony or
asynchrony?
Measles cases per month, Niger
New Zealand measles incidence
Hayman et al., unpublished
Human measles outbreaks: Reffective
Hayman et al., unpublished
Reffective (R0 )– average number of secondary cases in an immune population
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Measles transmission pathways
Prevalence in populations
Contact rates
Probability of infection
Spillover dynamics
Ebolavirus transmission dynamics
Reservoir dynamics
Interesting framework?
Comparison and summary
• Introductions into „naïve‟ populations
• Seasonality in contact rates
• Seasonality in infection prevalence in
reservoir
• Reservoir dynamics need to be
understood to understand and
reduce risk
Phylogenetics
Negative sense ssRNA viruses
Mononegavirales
Paramyxoviridae Rhadoviridae Filoviridae Bornaviridae
Rubulovirus Lyssavirus Marburgvirus Bornavirus
Morbillivirus Vesiculovirus Ebolavirus
Henipavirus … Cuevavirus
Pneumovirinae …
Metapneumovirus
…
Viral phylogeny – what „history‟ tells us
Rhabdovirus phylogenetics
Bourhy et al., JGV 2005
Banyard et al., Adv. Virus Res., 2011
Lyssavirus phylogenetics
Lyssavirus phylogenetics
Badrane and Tordo, J Virol, 2001
7000-11,630
years ago
800-1460
years ago
Negative sense ssRNA viruses
Mononegavirales
Paramyxoviridae Rhadoviridae Filoviridae Bornaviridae
Rubulovirus Lyssavirus Marburgvirus Bornavirus
Morbillivirus Vesiculovirus Ebolavirus
Henipavirus … Cuevavirus
Pneumovirinae …
Metapneumovirus
…
Viral phylogeny – what „history‟ tells us
Drexler et al., 2012 Nature Communications
Drexler et al., 2012 Nature Communications
Paramyxoviridae
Negative sense ssRNA viruses
Mononegavirales
Paramyxoviridae Rhadoviridae Filoviridae Bornaviridae
Rubulovirus Lyssavirus Marburgvirus Bornavirus
Morbillivirus Vesiculovirus Ebolavirus
Henipavirus … Cuevavirus
Pneumovirinae …
Metapneumovirus
…
Viral phylogeny – what „history‟ tells us
Distributions of species linked to filoviruses
Marburgvirus
Zaire ebolavirus
Reston ebolavirus
Lloviu virus
Olival and Hayman, 2013 Viruses
Negative sense ssRNA viruses
Mononegavirales
Paramyxoviridae Rhadoviridae Filoviridae Bornaviridae
Rubulovirus Lyssavirus Marburgvirus Bornavirus
Morbillivirus Vesiculovirus Ebolavirus
Henipavirus … Cuevavirus
Pneumovirinae …
Metapneumovirus
…
Viral phylogeny – what „history‟ tells us
Mononegavirales
Grard et al., PLoS Pathoges, 2012
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Photo Credit: Dr. Frederick Murphy/CDC
A matter of time?
Negative sense ssRNA viruses
Mononegavirales
Paramyxoviridae Rhadoviridae Filoviridae Bornaviridae
Rubulovirus Lyssavirus Marburgvirus Bornavirus
Morbillivirus Vesiculovirus Ebolavirus
Henipavirus … Cuevavirus
Pneumovirinae …
Metapneumovirus
…
Questions
Spillover dynamics
Marburgvirus transmission dynamics
Intra- and inter-
species
transmission
Reservoir dynamics
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Marburgvirus transmission pathways
Olival and Hayman, 2013 Viruses
Sensitivity analyses
Hayman et al., unpublished
New Zealand measles incidence
Hayman et al., unpublished
New Zealand measles incidence
Hayman et al., unpublished
Measles vaccination coverage (%), 2012
Hayman et al., unpublished
Global trend in annual measles incidence
Hayman et al., unpublished
Pathogen genotype
Prevalence
Immunity
Dose
Exposure duration
Pathogen genotype
Prevalence
Immunity
Dose
Exposure duration Human-human
transmission
Social, ecological and political practices
Impacts on
ecological
structure and
function
Cross-
species
transmission
Pathogen genotype
Prevalence
Immunity
Dose
Exposure duration
Vector-host
transmission
β
Environmental
transmission